Anatomy Tip Structures of the Heart In an effort to aid Health Information Management Coding Professionals for ICD-10, the following anatomy tip is provided with an educational intent. TIP: The Heart is made up of three main structures: 1. The Pericardium 2. The Heart Wall 3. The Chambers of the Heart The pericardium surrounds the heart. The outer layer, called the fibrous pericardium, secures the heart to surrounding structures like the blood vessels and the diaphragm. The inner layer, called the serous pericardium, is a double-layered section of the heart. Inside the two layers, serous fluid, known as pericardial fluid, lubricates and helps the heart move fluidly when beating. The heart wall is made up of three tissue layers: the epicardium, the myocardium, and the endocardium. The epicardium, which is the outermost layer, is also known as the visceral pericardium because it is also the inner wall of the pericardium. The middle layer, known as the myocardium, is formed out of contracting muscle. The endocardium, the innermost layer, covers heart valves and acts as a lining of the heart chambers. It is also in contact with the blood that is pumped through the heart, in order to push blood into the lungs and throughout the rest of the body. The four heart chambers are crucial to the heart’s function, composed of the atria, the right atrium and left atrium, and ventricles, the right ventricle and left ventricle. The right and left atria are thin-walled chambers responsible for receiving blood from veins, while the left and right ventricle are thick-walled chambers responsible for pumping blood out of the heart. References Okabe, Jerry M., et. al. Advanced Anatomy and Physiology for ICD-10-CM/PCS. Salt Lake City, UT: Contexo Media, 2011. Print. Clayman, Charles B. The Human Body: an Illustrated Guide to Its Structure, Function, and Disorders. London: Dorling Kindersley Pub., 1995. Print. Walker, Richard. E.guides: Human Body. New York, NY: DK Pub., 2005. Print. Walker, Richard. Guide to the Human Body. Buffalo, NY: Firefly Books, 2004. Print This Anatomy and Physiology tip sheet was developed by the CHIA Coding and Data Quality Committee as an educational resource 2012. Copyright © California Health Information Association, 2012.